Excavating equipment used in mining, construction and a myriad of other ground engaging operations typically includes a series of spaced apart ground engaging tools which project forward and serve to break up material to be gathered into a bucket of such excavating equipment. To enhance the ability of such ground engaging tools to break up the material in advance of a forward edge of the excavating bucket or the like, the tools are arranged in side-by-side and horizontal proximity relative to each other.
Such ground engaging tools can take a myriad of shapes and sizes. As used herein, the phrase “tools” is purposefully intended to include lip protectors, lip shrouds, rippers and other ground engaging tools including, but not limited to, ground engaging tooth assemblies. For exemplary purposes, the present invention is illustrated and described for use with a two-piece ground engaging tooth assembly. As mentioned, however, the present invention is equally applicable to other ground engaging equipment adapted for releasable securement to a forward edge or lip of an bucket or related excavating equipment.
The art recognized long ago the advantages to be gained by constructing each digging tooth as a two-part system. That is, the art recognized the advantages to be obtained by connecting a ground engaging tooth or tool to an adapter or support which, in turn, is connected to the bucket of excavating equipment. Typically, the adapter or support is provided with a base portion which is configured for attachment to the forward lip or blade of a bucket and a free ended nose portion. The digging tool is typically provided with a blind cavity or pocket whereby allowing the tool to fit over and along the adapter nose portion. As will be appreciated by those skilled in the art, the size of the adapter and digging tooth vary depending upon the particular digging application. For example, a two-part digging tooth system can vary in weight between a few pounds, i.e., three to five pounds, to two-hundred pounds.
In some digging operations, such teeth assemblies are subjected to highly abrasive conditions and, thus, experience considerable and rapid wear. Unless the conjuncture between the component parts of the two-part system is properly fitted, wear problems, especially in the pocket or cavity of the replacement part and along the nose portion of the adapter, can result. Moreover, the relatively high forces developed during some digging operations furthermore add to the rapid wear of the component parts of the digging tooth assembly.
In service, and although specific steps can be taken during fabrication of the digging teeth to prolong the usefulness thereof, a forward cutting edge of the replacement part sometimes quickly wears and become dull and, thus, inefficiencies in the digging operation develop thereby requiring replacement of such parts. As mentioned, the multipiece or two-part construction of such a tooth assembly advantageously allows the digging or excavating tool to be replaced independent of the adapter. Depending upon conditions, a given adapter can be successfully equipped with anywhere from five to thirty replacement digging teeth to maintain sharp penetrating edges. In the field, replacement of worn excavating or digging teeth is a common and sometimes a daily experience.
It is well known in the industry to releasably interconnect the component parts of the two-piece assembly with an elongated retaining pin. Removing or separating a worn or otherwise broken tool from its support, however, can involve a tedious and often difficult task of pounding the retaining pin from registering apertures in component parts of the two-piece assembly. Removal of the retaining pin is typically effected by using a large hammer to manually and endwise force the retaining pin from the apertures in the digging tooth and adapter. Of course, with larger two-part digging systems, the retaining pins are proportionately sized larger thereby adding to the manual effort and, thus, increasing the time and effort involved to effect digging tooth replacement and/or repair. Problems involving the hammer missing the punch or other tool used to removably pound the retaining pin and hitting the hand of the operator are well known. Of course, similar problems exist when the retaining pin is again pounded into the apertures to effect reattachment of the replacement part to the adapter. The unavailability of appropriate tools, i.e., hammers and punches, in the field is also a consistent and well known problem.
Many two part digging tool systems arrange the retaining pin along a generally horizontal axis. As will be appreciated by those skilled in the art, with the digging tooth assemblies being mounted in side-by-side relation relative to each other across the bucket lip, the horizontal disposition of the retainer pin for each digging system only adds to the time and effort required to initially remove the pin, whereby allowing for removal/repair of the worn/broken part of the two-part digging system and, subsequently, reinsertion of the pin into the registered apertures in the replacement part and adapter. Some operators utilize specially designed tools to facilitate removal of the horizontal pins.
It is also known to arrange the retaining pin in a generally vertical orientation. While advantageously enhancing access to the retaining pin, such retaining devices are more susceptible to the forces applied thereto as a result of the generally vertical movements of the bucket during a digging/excavating operation. Moreover, with a vertically oriented pin system, the lower hole or aperture in the replacement part of the two-part digging system is more exposed—as compared to a horizontal pinning system—to the ground surface over which the digging implement or bucket moves during a digging operation.
In any digging or excavating operation, contaminants including rocks, dust, dirt fines, moisture, and etc. furthermore exacerbate removal of the retaining pin. During any digging or excavating operation, small rocks, stones, dirt, dirt fines, and dust quickly accumulate, fill, and pack into holes or apertures in the digging tooth and adapter. As will be appreciated, moisture readily and quickly moves between confronting surfaces formed at the conjuncture of the digging tooth and adapter and passes toward the retaining pin. Moisture tends to corrode and rust or oxidize on the surfaces of both the retainer pin and closed margins of the apertures in the digging tooth and adapter thereby adding to the problem of retaining pin removal. Moreover, such moisture often combines with the small rocks, stones, dirt, dirt fines, and dust already packed and filled into the apertures or holes of the component parts of the two-part tooth system, thereby adding to the considerable labor already involved with effecting tooth replacement.
Using threaded devices for releasably interconnecting component parts of a two-part tooth system has been previously proposed. For example, U.S. Pat. Nos. 5,337,495 and 6,052,927 to S. Pippins disclose an externally threaded tooth point bolt in combination with an insert for releasably maintaining a digging tooth and adapter in operable combination relative to each other. Like others before, the Pippins devices do not solve the problem of having contaminants including small rocks, stones, dirt, dirt fines, dust, and moisture passing into the apertures and onto both internal and external threads of the interconnecting devices thereby resulting in clogging, oxidation and corrosion of the mating surfaces. Of course, contamination of any mating threaded surfaces as by clogging, oxidation or rusting can only further add to the problems of disconnecting the related parts relative to each other when servicing of the worn part of the two-part system, is required. Moreover, the Pippins devices fail to disclose any means for inhibiting wear between the component parts of a two-part digging tooth system.
Thus, there is a continuing need and desire for a pin assembly used to releasably and operably maintain component parts of a two-part ground engaging tooth system in operable combination relative to each other.